QUÉBEC CITY, Canada - In a match-up between two players who just would not give up, Lucie Safarova rallied from the clutches of defeat to beat Melanie Oudin, 46 62 64, and move into the semifinals of the Bell Challenge.

Safarova, the No.3 seed and a finalist here last year, was down 3-0 in the third set and even faced two points for a 4-0 deficit before turning things around, winning five games in a row to lead 5-3 and eventually serving it out comfortably.

"When I was down in the final set I still believed and kept on fighting. I waited for my chances and took them," Safarova said. "I didn't feel great at the start but I improved. We both played a great third set. I'm very happy to win."

"I'm disappointed right now," Oudin, who was the No.5 seed, said. "I had my chances but Lucie just came up with some incredible shots at the right times."

Next up for Safarova is another former runner-up here, Bethanie Mattek-Sands. Mattek-Sands, who made her first Sony Ericsson WTA Tour final here two years ago, took another step closer to a second career final at the same stop, beating Canadian Rebecca Marino in the first evening match, 64 76(4). She led 64 42 before the young Canadian rallied; but in the end the American held on.

"Rebecca has a big serve and a big forehand and these courts suit her," Mattek-Sands said. "I was ready for her though. My returns are one of my strengths."

"She has a lot of heart and a lot of variety, and she's tough to play," Marino said. "I would have liked to serve better but I didn't play too badly - she played well. She hit some incredible shots. I feel I've built a little momentum over the summer, and I hope to continue building that over the next few weeks."

Earlier in the day, teenagers Tamira Paszek and Christina McHale snapped up semifinal spots. Paszek nearly let a 63 51 lead slip but managed to close out No.8 seed Sofia Arvidsson, 63 64, while McHale beat Alexa Glatch, 63 61.

"I'm really excited to be in my first semifinal," the 18-year-old McHale said. "Alexa has a good serve so I had to be ready on my return, and I was more consistent. There were a few close games where things could have turned."

Paszek, 18, will be going for her third career final, having won Portoroz in 2006 and finishing runner-up at Bali in 2008 (to Patty Schnyder).